Claim 80 percent of something people value and chances are good that scrutiny and criticism will follow. That’s the case with irrigated crops in California.

California agriculture uses 80 percent of the state’s water. In turn, the state’s growers supply a third of the vegetables in the United States … and two-thirds of the fruit and nuts. The state is the largest producer of almonds and pistachios in the world. Enjoy a domestic artichoke, and chances are great it came from California: the state supplies close to 100 percent of the U.S. artichoke crop, and about four-fifths of those come from just one California county, Monterey County, where Castroville calls itself the artichoke capital of the world. (A number of Mediterranean countries produce more and no doubt reject any U.S. “We’re Number One” claim.)

In recent weeks, after a spate of vitriolic barbs aimed at those watering lawns in the desert, and coming after emergency drought legislation for the first time forcing cities and towns to cut water use, California’s irrigated agriculture has become a prime target. And the almond has become one of the most criticized crops. It takes about a gallon of water to produce one almond, and almonds account for 11 percent of the state’s agricultural water use. Fruit, nuts and alfalfa combined require 40 percent of California’s fresh water withdrawals, and they too are getting a critical look.

Fruits and Nuts … Lots of Water, Lots of Money

Josué Medellin-Azuara, a senior researcher at the University of California Davis Center for Watershed Sciences, says that fruits and nuts are grown on about one-third of the irrigated crop land and use a third of the water, but account for almost half of the total crop revenues for the agriculture sector in the state. Those proportions and that economic link compound the challenge of reconciling with a troubling, yet uncertain, water future. Add to it that permanent crops and irrigated crops like alfalfa and feed corn provide further value along their supply chains, and the political challenge only increases.

The ratio of permanent crops versus field crops, the latter planted seasonally, has increased as a share of irrigated crops in California since the 1990s. The amount of land under permanent irrigation also is increasing, and over the past two decades many farmers across the state have switched from cotton and alfalfa to almonds. “These are high value crops and much higher revenue per unit area, which makes these attractive for farmers,” says Medellin-Azuara. “But if we keep increasing permanent crops in the state, it reduces the flexibility in the system.”

According to the Public Policy Institute of California, the shift to high-value perennial crops has increased the value of farm output from $16.3 billion of gross state product in 1998 to $36.4 billion in 2012.

Fruit and nut trees and grape vines need a minimum amount of water year in and year out. And unlike field crops, almond and pistachio trees and fruit orchards can’t lie fallow. “Having too many (permanent crops) reduces the way we cope with drought and makes fallowing more expensive,” Medellin-Azuara says.

Yet flexibility in agriculture is just what the state needs in a future characterized by a warming climate, says water ecologist John Matthews, of the Alliance for Global Water Adaptation. Fruit and nut trees are a lot like having big, rigid infrastructure requiring vast quantities of water for decades, he says. “That is a serious commitment, and it sets a clear floor to your water commitment for a long time,” Matthews says.

Prospects for slow-motion train wreck

With this configuration of high-value crops needing a fixed amount of water, Matthews says it will be difficult for California to modify its agriculture economy. He says the drought and the ricochet-effect of over-pumping groundwater, which will take decades to recharge, is like watching a train wreck happen in slow motion. Extreme weather conditions and severe drought are more likely to occur again in the future with climate change than in the climate that has existed since California’s economy was built around agriculture. Globally, agriculture uses about 70 percent of water withdrawals, so California’s 80 percent share isn’t that much higher than the norm. But it does make it more vulnerable to extremes.

California now is planning for an uncertain future, but warnings of a need for aggressive action on water supplies date back more than a decade. A report published in 2004 in the Proceedings of the National Academy of Sciences was just one of a number of studies suggesting problems ahead.

“Flexibility really is the key to climate preparedness,” Texas Tech University climate scientist Katharine Hayhoe, lead author of that study, wrote in an e-mail exchange with Yale Climate Connections. “The main reason why we humans even care about climate change is because we have built our vulnerabilities into our systems. A thousand years ago, if climate shifted or sea level rose, what would we do? We’d pick up our tents and our farming implements and move.

“Today, that option is no longer available. That’s why we need to be more flexible in the places where we live, in many ways; from building new neighborhoods that float, in the Netherlands; to plowing biochar back into our fields in Iowa to better retain water and nutrients as well as sequestering carbon; to diversifying our crops such that they are able to withstand very different future conditions than the ones we have seen in the past.”

Fundamentally, agriculture needs water, and certain crops need far more than others. Drought offers clear challenges, but also an opportunity for change, for diversification, and for seeking out better ways to manage agriculture for drought conditions, and to improve efficiencies.

A key question as yet unanswered is whether water use for agriculture in crop-rich California can coexist with other priority uses and needs and with the state’s growing population. And, if so, how?